Many cultivars of the Vinifera-type are self-unfruitful, and require another cultivar with an overlapping flowering period to be interplanted. In some cultivars, pruning affects the effectiveness of the pollen. Spraying "tame" grapes for control of insects and diseases is essential to production of fruit. However, the problems are different in different places. Each grower should study his conditions and apply only such sprays as found necessary and recommended. Infection must be prevented if clean fruit is to be produced. Thoroughness is very essential. Grapes are very sensitive to injury from 2,4-D. Grapes are affected by a great many fungi, bacteria, viruses, nematodes, insects, and mineral deficiencies. Local problems should be resolved with local agricultural agents. Eastman (1992) presents a wealth of natural history data applying to wild grapes and I excerpt here. Martin et al. note that, except for the Japanese beetle (Popillia japonica), wild grapes have few serious pests. Feeding on almost 300 plant species, it favors grape. I suspect that many of the pests of the wild grapes will be even worse on "tame" grapes. Conversely, I suspect that, proportionately, the wild grapes are stronger, on average, than the tame grapes. Many gamebirds (dove, duck, grouse, pheasant, pigeon, prairie chicken, quali, turkey) relish the fruit. Migrating south, Tennessee warblers sometimes descend on grapevines to feed. Martin et al. list dozens of songbirds indulging in grapes (e.g., blackbird, bluebird, catbird, finch, flicker, etc.), sometimes constituting 50% of the diet of mockingbirds, less than 25% of cardinal, fox sparrow, robin, and wax-wing. Songbirds collect shreddy grapevine bark as a favorite material for nests (e.g., red-eyed vireo, gray catbird, Northern mockingbird, brown thrasher, and Northern cardinal). Raccoons often deposit scat with grape seeds at bases of trees. Other fruit feeders include black bears, coyote, fox, opossum, rabbit, raccoon, skunk, and squirrel. Deer graze the herbage (EAS; MZN). Causing diamond-shaped cankers on vines, resulting in dead branches and small angular spots with yellowish margins on leaves, is a widespread sac fungus (Cryptosporella viticola; dead-arm disease or branch necrosis). A "landscape scene" growing on the dead inner bark of a grapevine is a mycelial fan, probably Armillaria. At night, the fungus sometimes casts a faint luminescent glow. Fleshy, pea-shaped galls on leaf undersides with openings on the upper leaf surface indicate yellowish-green grape phylloxera (Phylloxera vitifoliae), this plant's most injurious aphid. Aphid generations migrating to the roots, feeding and forming nodules, may kill the vine. Green or red conical galls, like dunce caps on upper leaf surfaces are Cecidomyia viticola, the grape gall or tube midge. The grapevine tomato gall midge (Lasioptera vitis) may make greenish or reddish pea-size swellings on leaf veins and tendrils. Large, rear-horned sphinx caterpillars, some of which make squeaking sounds, are easily recognized. The patterns of adult wood-nymph moths (Eudryas) resemble bird droppings. The eight-spotted forester (Alypia octomaculata), a bluish-white caterpillar banded with orange, can defoliate vines. Grapevine loopers (Eulithis), slender, pale green inchworms, pupate in loose webs on the foliage. Dyspteris aborivaria, another inchworm (badwing geometer), rolls grape leaves, as does the grape plume moth (Geina periscelidactyla). A smoky black spotted spinulose caterpillar, the grapeleaf skeletonizer (Harrisina americana), feeds on upper leaf surfaces, consuming all but the veins. Roundish, white, clear-winged moth caterpillars may be grape root borers (Vitacea polistiformis), which drop to the ground and bore into the roots. The adults resemble paper wasps, even mimicking their behavior. In summer, an inch-long tan beetle with black spots on each side, the spotted grapevine beetle (Pelidnota punctata), draws leaves together making its tent.
The grape curculio (Craponius inaequalis) lays eggs, first feeding on the leaves. Larvae then excavate the green berry pulp beneath the skin. Caterpillars of the grape berry moth (Paralobesia viteana) web several ripe berries together or to leaves, making a hole in each berry. The caterpillar folds over a leaf and pupates inside the fold. Folded leaves may hang on the vine in winter. The large Virginia creeper sphinx moth, also called hog sphinx (Darapsa myron), punctures decaying or fermented fruit to feed, as do bees and wasps.
In general, agricultural selection breeds out some of the natural pesticides, like resveratrol, which also have many interesting biological activities. The recent American Chemical Society book, Wine, Nutritional and Therapeutic Benefits (Watkins, T.R., 1997), heaps praise on resveratrol, failing to tell us that there is 10 to 100 times more in the leaves, and I suspect seeds, than in the fruit pulp and wines. The seeds have only recently come to the market and clinical trials are few and far between. On the other hand, the fruits contain more than 30 types of anthocyanins. Small wonder that grape juice has 4 times the ORAC score of any other fruit juice studied (JNU). Resveratrol has received much press for cancer prevention. For example, Stewart et al. (2003), commenting on resveratrol as a candidate for prostate cancer prevention, comment that it may constitute 5 to 10% of grapeskin. "Resveratrol may represent the tip of the iceberg of a broad class of stilbene and related polyphenolic natural products," possibly safe and effective agents for cancer prevention. They look to resveratrol as a leading agent for prostate cancer prevention because it inhibits each stage of multistage carcinogenesis, and scavenges incipient populations of androgen-dependent and androgen-independent prostate cancer cells (X12840221). Resveratrol protects against colitis, and has antioxidant and apoptotic actvities. At levels of 5 to 10 mg/kg/day (equivalent to 1 g/day if I were the 100-kg rat), resveratrol reduced colonic injury, index of neutrophil infiltration, and levels of cytokine (X15013856). But I like to remind readers that it is a cocktail of closely related compounds, piceatannol and pterostilbene deserving almost as much praise as the resveratrol (X15309446). Many other anticancer activities are listed in the USDA database. Working with tissue culture, Jo et al. (2005) found potent topoisomerase II catalytic inhibitors: TP fractions 4 and 6 (IC50 = 0.28-0.29 pg/ml), TP-3 (IC50 = 0.74 pg/ml), and crude extract (IC50 = 1.02 pg/ml) — each significantly more potent than resveratrol (IC50 = 18.0 pg/mL) (X15796584). Preliminary data and literature searches suggest that the leaves may be a better source of resveratrol, ironically, leaves stressed by disease, insects, and physical damage (JAD). A study by Fernandez-Pachon et al. (2005) confirms what I had long heard: that red wine increases uric acid levels. That can be good in normou-ricemic humans, but may induce a gout crisis in hyperuricemic individuals. Maximum concentrations of maximum antioxidant capacity (and uric acid) occurred after about an hour. Uric acid, like albumin and bilirubin, is an endogenous antioxidant as well (X15941351).
Was this article helpful?
Learning About 10 Ways Fight Off Cancer Can Have Amazing Benefits For Your Life The Best Tips On How To Keep This Killer At Bay Discovering that you or a loved one has cancer can be utterly terrifying. All the same, once you comprehend the causes of cancer and learn how to reverse those causes, you or your loved one may have more than a fighting chance of beating out cancer.